C++ Constant::getType方法代码示例

void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
  // Check to see if this is a special global used by LLVM, if so, emit it.
  if (!GV->hasInitializer() ||
      EmitSpecialLLVMGlobal(GV))
    return;

  const TargetData *TD = TM.getTargetData();
  OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GV, Mang,TM));

  
  MCSymbol *GVSym = Mang->getSymbol(GV);
  Constant *C = GV->getInitializer();
  unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
  
  // Mark the start of the global
  OutStreamer.EmitRawText("\t.cc_top " + Twine(GVSym->getName()) + ".data," +
                          GVSym->getName());

  switch (GV->getLinkage()) {
  case GlobalValue::AppendingLinkage:
    report_fatal_error("AppendingLinkage is not supported by this target!");
  case GlobalValue::LinkOnceAnyLinkage:
  case GlobalValue::LinkOnceODRLinkage:
  case GlobalValue::WeakAnyLinkage:
  case GlobalValue::WeakODRLinkage:
  case GlobalValue::ExternalLinkage:
    emitArrayBound(GVSym, GV);
    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);

    // TODO Use COMDAT groups for LinkOnceLinkage
    if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
    // FALL THROUGH
  case GlobalValue::InternalLinkage:
  case GlobalValue::PrivateLinkage:
  case GlobalValue::LinkerPrivateLinkage:
    break;
  case GlobalValue::DLLImportLinkage:
    llvm_unreachable("DLLImport linkage is not supported by this target!");
  case GlobalValue::DLLExportLinkage:
    llvm_unreachable("DLLExport linkage is not supported by this target!");
  default:
    llvm_unreachable("Unknown linkage type!");
  }

  EmitAlignment(Align > 2 ? Align : 2, GV);
  
  unsigned Size = TD->getTypeAllocSize(C->getType());
  if (GV->isThreadLocal()) {
    Size *= MaxThreads;
  }
  if (MAI->hasDotTypeDotSizeDirective()) {
    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
    OutStreamer.EmitRawText("\t.size " + Twine(GVSym->getName()) + "," +
                            Twine(Size));
  }
  OutStreamer.EmitLabel(GVSym);
  
  EmitGlobalConstant(C);
  if (GV->isThreadLocal()) {
    for (unsigned i = 1; i < MaxThreads; ++i)
      EmitGlobalConstant(C);
  }
  // The ABI requires that unsigned scalar types smaller than 32 bits
  // are padded to 32 bits.
  if (Size < 4)
    OutStreamer.EmitZeros(4 - Size, 0);
  
  // Mark the end of the global
  OutStreamer.EmitRawText("\t.cc_bottom " + Twine(GVSym->getName()) + ".data");
}

// llvm_asm_file_end - Finish the .s file.
void llvm_asm_file_end(void) {
  timevar_push(TV_LLVM_PERFILE);
  llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.

  if (flag_pch_file) {
    writeLLVMTypesStringTable();
    writeLLVMValues();
  }

  // Add an llvm.global_ctors global if needed.
  if (!StaticCtors.empty())
    CreateStructorsList(StaticCtors, "llvm.global_ctors");
  // Add an llvm.global_dtors global if needed.
  if (!StaticDtors.empty())
    CreateStructorsList(StaticDtors, "llvm.global_dtors");
  
  if (!AttributeUsedGlobals.empty()) {
    const Type *SBP = PointerType::get(Type::Int8Ty);
    ArrayType *AT = ArrayType::get(SBP, AttributeUsedGlobals.size());
    Constant *Init = ConstantArray::get(AT, AttributeUsedGlobals);
    GlobalValue* gv = new GlobalVariable(AT, false, 
                       GlobalValue::AppendingLinkage, Init,
                       "llvm.used", TheModule);
    gv->setSection("llvm.metadata");
    AttributeUsedGlobals.clear();
  }
  
  // Add llvm.noinline
  if (!AttributeNoinlineFunctions.empty()) {
    const Type *SBP= PointerType::get(Type::Int8Ty);
    ArrayType *AT = ArrayType::get(SBP, AttributeNoinlineFunctions.size());
    Constant *Init = ConstantArray::get(AT, AttributeNoinlineFunctions);
    GlobalValue *gv = new GlobalVariable(AT, false, 
                                        GlobalValue::AppendingLinkage, Init,
                                        "llvm.noinline", TheModule);
    gv->setSection("llvm.metadata");
    
    // Clear vector
    AttributeNoinlineFunctions.clear();
  }
  
  // Add llvm.global.annotations
  if (!AttributeAnnotateGlobals.empty()) {
    
    Constant *Array =
    ConstantArray::get(ArrayType::get(AttributeAnnotateGlobals[0]->getType(), 
                                      AttributeAnnotateGlobals.size()),
                       AttributeAnnotateGlobals);
    GlobalValue *gv = new GlobalVariable(Array->getType(), false, 
                                         GlobalValue::AppendingLinkage, Array, 
                                         "llvm.global.annotations", TheModule); 
    gv->setSection("llvm.metadata");
    AttributeAnnotateGlobals.clear();
  
  }
  
  // Finish off the per-function pass.
  if (PerFunctionPasses)
    PerFunctionPasses->doFinalization();
    
  // Run module-level optimizers, if any are present.
  if (PerModulePasses)
    PerModulePasses->run(*TheModule);
  
  // Run the code generator, if present.
  if (CodeGenPasses) {
    CodeGenPasses->doInitialization();
    for (Module::iterator I = TheModule->begin(), E = TheModule->end();
         I != E; ++I)
      if (!I->isDeclaration())
        CodeGenPasses->run(*I);
    CodeGenPasses->doFinalization();
  }

  AsmOutStream->flush();
  fflush(asm_out_file);
  delete AsmOutStream;
  AsmOutStream = 0;
  delete AsmOutFile;
  AsmOutFile = 0;
  timevar_pop(TV_LLVM_PERFILE);
}

/// emit_global_to_llvm - Emit the specified VAR_DECL or aggregate CONST_DECL to
/// LLVM as a global variable.  This function implements the end of
/// assemble_variable.
void emit_global_to_llvm(tree decl) {
  if (errorcount || sorrycount) return;

  // FIXME: Support alignment on globals: DECL_ALIGN.
  // FIXME: DECL_PRESERVE_P indicates the var is marked with attribute 'used'.

  // Global register variables don't turn into LLVM GlobalVariables.
  if (TREE_CODE(decl) == VAR_DECL && DECL_REGISTER(decl))
    return;

  timevar_push(TV_LLVM_GLOBALS);

  // Get or create the global variable now.
  GlobalVariable *GV = cast<GlobalVariable>(DECL_LLVM(decl));
  
  // Convert the initializer over.
  Constant *Init;
  if (DECL_INITIAL(decl) == 0 || DECL_INITIAL(decl) == error_mark_node) {
    // This global should be zero initialized.  Reconvert the type in case the
    // forward def of the global and the real def differ in type (e.g. declared
    // as 'int A[]', and defined as 'int A[100]').
    Init = Constant::getNullValue(ConvertType(TREE_TYPE(decl)));
  } else {
    assert((TREE_CONSTANT(DECL_INITIAL(decl)) || 
            TREE_CODE(DECL_INITIAL(decl)) == STRING_CST) &&
           "Global initializer should be constant!");
    
    // Temporarily set an initializer for the global, so we don't infinitely
    // recurse.  If we don't do this, we can hit cases where we see "oh a global
    // with an initializer hasn't been initialized yet, call emit_global_to_llvm
    // on it".  When constructing the initializer it might refer to itself.
    // this can happen for things like void *G = &G;
    //
    GV->setInitializer(UndefValue::get(GV->getType()->getElementType()));
    Init = TreeConstantToLLVM::Convert(DECL_INITIAL(decl));
  }

  // If we had a forward definition that has a type that disagrees with our
  // initializer, insert a cast now.  This sort of thing occurs when we have a
  // global union, and the LLVM type followed a union initializer that is
  // different from the union element used for the type.
  if (GV->getType()->getElementType() != Init->getType()) {
    GV->removeFromParent();
    GlobalVariable *NGV = new GlobalVariable(Init->getType(), GV->isConstant(),
                                             GlobalValue::ExternalLinkage, 0,
                                             GV->getName(), TheModule);
    GV->replaceAllUsesWith(ConstantExpr::getBitCast(NGV, GV->getType()));
    delete GV;
    SET_DECL_LLVM(decl, NGV);
    GV = NGV;
  }
 
  // Set the initializer.
  GV->setInitializer(Init);

  // Set thread local (TLS)
  if (TREE_CODE(decl) == VAR_DECL && DECL_THREAD_LOCAL(decl))
    GV->setThreadLocal(true);

  // Set the linkage.
  if (!TREE_PUBLIC(decl)) {
    GV->setLinkage(GlobalValue::InternalLinkage);
  } else if (DECL_WEAK(decl) || DECL_ONE_ONLY(decl) ||
             (DECL_COMMON(decl) &&  // DECL_COMMON is only meaningful if no init
              (!DECL_INITIAL(decl) || DECL_INITIAL(decl) == error_mark_node))) {
    // llvm-gcc also includes DECL_VIRTUAL_P here.
    GV->setLinkage(GlobalValue::WeakLinkage);
  } else if (DECL_COMDAT(decl)) {
    GV->setLinkage(GlobalValue::LinkOnceLinkage);
  }

#ifdef TARGET_ADJUST_LLVM_LINKAGE
  TARGET_ADJUST_LLVM_LINKAGE(GV,decl);
#endif /* TARGET_ADJUST_LLVM_LINKAGE */

  // Handle visibility style
  if (TREE_PUBLIC(decl)) {
    if (DECL_VISIBILITY(decl) == VISIBILITY_HIDDEN)
      GV->setVisibility(GlobalValue::HiddenVisibility);
    else if (DECL_VISIBILITY(decl) == VISIBILITY_PROTECTED)
      GV->setVisibility(GlobalValue::ProtectedVisibility);
  }

  // Set the section for the global.
  if (TREE_CODE(decl) == VAR_DECL || TREE_CODE(decl) == CONST_DECL) {
    if (DECL_SECTION_NAME(decl)) {
      GV->setSection(TREE_STRING_POINTER(DECL_SECTION_NAME(decl)));
#ifdef LLVM_IMPLICIT_TARGET_GLOBAL_VAR_SECTION
    } else if (const char *Section = 
                LLVM_IMPLICIT_TARGET_GLOBAL_VAR_SECTION(decl)) {
      GV->setSection(Section);
#endif
    }
    
    // Set the alignment for the global if one of the following condition is met
    // 1) DECL_ALIGN_UNIT does not match alignment as per ABI specification
    // 2) DECL_ALIGN is set by user.
//.........这里部分代码省略.........

bool SanitizerCoverageModule::runOnModule(Module &M) {
  if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
    return false;
  C = &(M.getContext());
  DL = &M.getDataLayout();
  CurModule = &M;
  IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
  Type *VoidTy = Type::getVoidTy(*C);
  IRBuilder<> IRB(*C);
  Type *Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
  Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
  Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
  Int64Ty = IRB.getInt64Ty();

  SanCovFunction = checkSanitizerInterfaceFunction(
      M.getOrInsertFunction(kSanCovName, VoidTy, Int32PtrTy, nullptr));
  SanCovWithCheckFunction = checkSanitizerInterfaceFunction(
      M.getOrInsertFunction(kSanCovWithCheckName, VoidTy, Int32PtrTy, nullptr));
  SanCovIndirCallFunction =
      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
          kSanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
  SanCovTraceCmpFunction =
      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
          kSanCovTraceCmp, VoidTy, Int64Ty, Int64Ty, Int64Ty, nullptr));
  SanCovTraceSwitchFunction =
      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
          kSanCovTraceSwitch, VoidTy, Int64Ty, Int64PtrTy, nullptr));

  // We insert an empty inline asm after cov callbacks to avoid callback merge.
  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
                            StringRef(""), StringRef(""),
                            /*hasSideEffects=*/true);

  SanCovTraceEnter = checkSanitizerInterfaceFunction(
      M.getOrInsertFunction(kSanCovTraceEnter, VoidTy, Int32PtrTy, nullptr));
  SanCovTraceBB = checkSanitizerInterfaceFunction(
      M.getOrInsertFunction(kSanCovTraceBB, VoidTy, Int32PtrTy, nullptr));

  // At this point we create a dummy array of guards because we don't
  // know how many elements we will need.
  Type *Int32Ty = IRB.getInt32Ty();
  Type *Int8Ty = IRB.getInt8Ty();

  GuardArray =
      new GlobalVariable(M, Int32Ty, false, GlobalValue::ExternalLinkage,
                         nullptr, "__sancov_gen_cov_tmp");
  if (Options.Use8bitCounters)
    EightBitCounterArray =
        new GlobalVariable(M, Int8Ty, false, GlobalVariable::ExternalLinkage,
                           nullptr, "__sancov_gen_cov_tmp");

  for (auto &F : M)
    runOnFunction(F);

  auto N = NumberOfInstrumentedBlocks();

  // Now we know how many elements we need. Create an array of guards
  // with one extra element at the beginning for the size.
  Type *Int32ArrayNTy = ArrayType::get(Int32Ty, N + 1);
  GlobalVariable *RealGuardArray = new GlobalVariable(
      M, Int32ArrayNTy, false, GlobalValue::PrivateLinkage,
      Constant::getNullValue(Int32ArrayNTy), "__sancov_gen_cov");


  // Replace the dummy array with the real one.
  GuardArray->replaceAllUsesWith(
      IRB.CreatePointerCast(RealGuardArray, Int32PtrTy));
  GuardArray->eraseFromParent();

  GlobalVariable *RealEightBitCounterArray;
  if (Options.Use8bitCounters) {
    // Make sure the array is 16-aligned.
    static const int kCounterAlignment = 16;
    Type *Int8ArrayNTy =
        ArrayType::get(Int8Ty, RoundUpToAlignment(N, kCounterAlignment));
    RealEightBitCounterArray = new GlobalVariable(
        M, Int8ArrayNTy, false, GlobalValue::PrivateLinkage,
        Constant::getNullValue(Int8ArrayNTy), "__sancov_gen_cov_counter");
    RealEightBitCounterArray->setAlignment(kCounterAlignment);
    EightBitCounterArray->replaceAllUsesWith(
        IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy));
    EightBitCounterArray->eraseFromParent();
  }

  // Create variable for module (compilation unit) name
  Constant *ModNameStrConst =
      ConstantDataArray::getString(M.getContext(), M.getName(), true);
  GlobalVariable *ModuleName =
      new GlobalVariable(M, ModNameStrConst->getType(), true,
                         GlobalValue::PrivateLinkage, ModNameStrConst);

  Function *CtorFunc;
  std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
      M, kSanCovModuleCtorName, kSanCovModuleInitName,
      {Int32PtrTy, IntptrTy, Int8PtrTy, Int8PtrTy},
      {IRB.CreatePointerCast(RealGuardArray, Int32PtrTy),
       ConstantInt::get(IntptrTy, N),
       Options.Use8bitCounters
           ? IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy)
           : Constant::getNullValue(Int8PtrTy),
//.........这里部分代码省略.........

void jl_dump_native(const char *bc_fname, const char *unopt_bc_fname, const char *obj_fname, const char *sysimg_data, size_t sysimg_len)
{
    JL_TIMING(NATIVE_DUMP);
    // We don't want to use MCJIT's target machine because
    // it uses the large code model and we may potentially
    // want less optimizations there.
    Triple TheTriple = Triple(jl_TargetMachine->getTargetTriple());
    // make sure to emit the native object format, even if FORCE_ELF was set in codegen
#if defined(_OS_WINDOWS_)
    TheTriple.setObjectFormat(Triple::COFF);
#elif defined(_OS_DARWIN_)
    TheTriple.setObjectFormat(Triple::MachO);
    TheTriple.setOS(llvm::Triple::MacOSX);
#endif
    std::unique_ptr<TargetMachine>
    TM(jl_TargetMachine->getTarget().createTargetMachine(
        TheTriple.getTriple(),
        jl_TargetMachine->getTargetCPU(),
        jl_TargetMachine->getTargetFeatureString(),
        jl_TargetMachine->Options,
#if defined(_OS_LINUX_) || defined(_OS_FREEBSD_)
        Reloc::PIC_,
#else
        Optional<Reloc::Model>(),
#endif
#if defined(_CPU_PPC_) || defined(_CPU_PPC64_)
        // On PPC the small model is limited to 16bit offsets
        CodeModel::Medium,
#else
        // Use small model so that we can use signed 32bits offset in the function and GV tables
        CodeModel::Small,
#endif
        CodeGenOpt::Aggressive // -O3 TODO: respect command -O0 flag?
        ));

    legacy::PassManager PM;
    addTargetPasses(&PM, TM.get());

    // set up optimization passes
    SmallVector<char, 128> bc_Buffer;
    SmallVector<char, 128> obj_Buffer;
    SmallVector<char, 128> unopt_bc_Buffer;
    raw_svector_ostream bc_OS(bc_Buffer);
    raw_svector_ostream obj_OS(obj_Buffer);
    raw_svector_ostream unopt_bc_OS(unopt_bc_Buffer);
    std::vector<NewArchiveMember> bc_Archive;
    std::vector<NewArchiveMember> obj_Archive;
    std::vector<NewArchiveMember> unopt_bc_Archive;
    std::vector<std::string> outputs;

    if (unopt_bc_fname)
        PM.add(createBitcodeWriterPass(unopt_bc_OS));
    if (bc_fname || obj_fname)
        addOptimizationPasses(&PM, jl_options.opt_level, true);
    if (bc_fname)
        PM.add(createBitcodeWriterPass(bc_OS));
    if (obj_fname)
        if (TM->addPassesToEmitFile(PM, obj_OS, TargetMachine::CGFT_ObjectFile, false))
            jl_safe_printf("ERROR: target does not support generation of object files\n");

    // Reset the target triple to make sure it matches the new target machine
    shadow_output->setTargetTriple(TM->getTargetTriple().str());
#if JL_LLVM_VERSION >= 40000
    DataLayout DL = TM->createDataLayout();
    DL.reset(DL.getStringRepresentation() + "-ni:10:11:12");
    shadow_output->setDataLayout(DL);
#else
    shadow_output->setDataLayout(TM->createDataLayout());
#endif

    // add metadata information
    if (imaging_mode) {
        emit_offset_table(shadow_output, jl_sysimg_gvars, "jl_sysimg_gvars");
        emit_offset_table(shadow_output, jl_sysimg_fvars, "jl_sysimg_fvars");

        // reflect the address of the jl_RTLD_DEFAULT_handle variable
        // back to the caller, so that we can check for consistency issues
        GlobalValue *jlRTLD_DEFAULT_var = shadow_output->getNamedValue("jl_RTLD_DEFAULT_handle");
        addComdat(new GlobalVariable(*shadow_output,
                                     jlRTLD_DEFAULT_var->getType(),
                                     true,
                                     GlobalVariable::ExternalLinkage,
                                     jlRTLD_DEFAULT_var,
                                     "jl_RTLD_DEFAULT_handle_pointer"));
    }

    // do the actual work
    auto add_output = [&] (Module &M, StringRef unopt_bc_Name, StringRef bc_Name, StringRef obj_Name) {
        PM.run(M);
        if (unopt_bc_fname)
            emit_result(unopt_bc_Archive, unopt_bc_Buffer, unopt_bc_Name, outputs);
        if (bc_fname)
            emit_result(bc_Archive, bc_Buffer, bc_Name, outputs);
        if (obj_fname)
            emit_result(obj_Archive, obj_Buffer, obj_Name, outputs);
    };

    add_output(*shadow_output, "unopt.bc", "text.bc", "text.o");

    LLVMContext &Context = shadow_output->getContext();
//.........这里部分代码省略.........

/// Replace direct callers of Old with New. Also add parameters to the call to
/// \p New, which are defined by the FuncIdx's value in \p Params.
bool SwiftMergeFunctions::replaceDirectCallers(Function *Old, Function *New,
                                   const ParamInfos &Params, unsigned FuncIdx) {
  bool AllReplaced = true;

  SmallVector<CallInst *, 8> Callers;
  
  for (Use &U : Old->uses()) {
    auto *I = dyn_cast<Instruction>(U.getUser());
    if (!I) {
      AllReplaced = false;
      continue;
    }
    FunctionEntry *FE = getEntry(I->getFunction());
    if (FE)
      removeEquivalenceClassFromTree(FE);
    
    auto *CI = dyn_cast<CallInst>(I);
    if (!CI || CI->getCalledValue() != Old) {
      AllReplaced = false;
      continue;
    }
    Callers.push_back(CI);
  }
  if (!AllReplaced)
    return false;

  for (CallInst *CI : Callers) {
    auto &Context = New->getContext();
    auto NewPAL = New->getAttributes();

    SmallVector<Type *, 8> OldParamTypes;
    SmallVector<Value *, 16> NewArgs;
    SmallVector<AttributeSet, 8> NewArgAttrs;
    IRBuilder<> Builder(CI);

    FunctionType *NewFuncTy = New->getFunctionType();
    (void) NewFuncTy;
    unsigned ParamIdx = 0;
    
    // Add the existing parameters.
    for (Value *OldArg : CI->arg_operands()) {
      NewArgAttrs.push_back(NewPAL.getParamAttributes(ParamIdx));
      NewArgs.push_back(OldArg);
      OldParamTypes.push_back(OldArg->getType());
      ++ParamIdx;
    }
    // Add the new parameters.
    for (const ParamInfo &PI : Params) {
      assert(ParamIdx < NewFuncTy->getNumParams());
      Constant *ArgValue = PI.Values[FuncIdx];
      assert(ArgValue != Old &&
        "should not try to replace all callers of self referencing functions");
      NewArgs.push_back(ArgValue);
      OldParamTypes.push_back(ArgValue->getType());
      ++ParamIdx;
    }

    auto *FType = FunctionType::get(Old->getFunctionType()->getReturnType(),
                                    OldParamTypes, false);
    auto *FPtrType = PointerType::get(FType,
                        cast<PointerType>(New->getType())->getAddressSpace());

    Value *Callee = ConstantExpr::getBitCast(New, FPtrType);
    CallInst *NewCI = Builder.CreateCall(Callee, NewArgs);
    NewCI->setCallingConv(CI->getCallingConv());
    // Don't transfer attributes from the function to the callee. Function
    // attributes typically aren't relevant to the calling convention or ABI.
    NewCI->setAttributes(AttributeList::get(Context, /*FnAttrs=*/AttributeSet(),
                                            NewPAL.getRetAttributes(),
                                            NewArgAttrs));
    CI->replaceAllUsesWith(NewCI);
    CI->eraseFromParent();
  }
  assert(Old->use_empty() && "should have replaced all uses of old function");
  return Old->hasLocalLinkage();
}

ConstantExpression::ConstantExpression(Constant constant) :
        constant { constant }
{
    auto type = constant.getType();
    setType(*type);
}

// Create a constant for Str so that we can pass it to the run-time lib.
static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
  Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
  return new GlobalVariable(M, StrConst->getType(), true,
                            GlobalValue::PrivateLinkage, StrConst, "");
}

bool GlobalMerge::doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
                          Module &M, bool isConst, unsigned AddrSpace) const {
  const TargetLowering *TLI = TM->getTargetLowering();
  const DataLayout *DL = TLI->getDataLayout();

  // FIXME: Infer the maximum possible offset depending on the actual users
  // (these max offsets are different for the users inside Thumb or ARM
  // functions)
  unsigned MaxOffset = TLI->getMaximalGlobalOffset();

  // FIXME: Find better heuristics
  std::stable_sort(Globals.begin(), Globals.end(),
                   [DL](const GlobalVariable *GV1, const GlobalVariable *GV2) {
    Type *Ty1 = cast<PointerType>(GV1->getType())->getElementType();
    Type *Ty2 = cast<PointerType>(GV2->getType())->getElementType();

    return (DL->getTypeAllocSize(Ty1) < DL->getTypeAllocSize(Ty2));
  });

  Type *Int32Ty = Type::getInt32Ty(M.getContext());

  assert(Globals.size() > 1);

  // FIXME: This simple solution merges globals all together as maximum as
  // possible. However, with this solution it would be hard to remove dead
  // global symbols at link-time. An alternative solution could be checking
  // global symbols references function by function, and make the symbols
  // being referred in the same function merged and we would probably need
  // to introduce heuristic algorithm to solve the merge conflict from
  // different functions.
  for (size_t i = 0, e = Globals.size(); i != e; ) {
    size_t j = 0;
    uint64_t MergedSize = 0;
    std::vector<Type*> Tys;
    std::vector<Constant*> Inits;

    bool HasExternal = false;
    GlobalVariable *TheFirstExternal = 0;
    for (j = i; j != e; ++j) {
      Type *Ty = Globals[j]->getType()->getElementType();
      MergedSize += DL->getTypeAllocSize(Ty);
      if (MergedSize > MaxOffset) {
        break;
      }
      Tys.push_back(Ty);
      Inits.push_back(Globals[j]->getInitializer());

      if (Globals[j]->hasExternalLinkage() && !HasExternal) {
        HasExternal = true;
        TheFirstExternal = Globals[j];
      }
    }

    // If merged variables doesn't have external linkage, we needn't to expose
    // the symbol after merging.
    GlobalValue::LinkageTypes Linkage = HasExternal
                                            ? GlobalValue::ExternalLinkage
                                            : GlobalValue::InternalLinkage;

    // If merged variables have external linkage, we use symbol name of the
    // first variable merged as the suffix of global symbol name. This would
    // be able to avoid the link-time naming conflict for globalm symbols.
    Twine MergedGVName = HasExternal
                             ? "_MergedGlobals_" + TheFirstExternal->getName()
                             : "_MergedGlobals";

    StructType *MergedTy = StructType::get(M.getContext(), Tys);
    Constant *MergedInit = ConstantStruct::get(MergedTy, Inits);

    GlobalVariable *MergedGV = new GlobalVariable(
        M, MergedTy, isConst, Linkage, MergedInit, MergedGVName, nullptr,
        GlobalVariable::NotThreadLocal, AddrSpace);

    for (size_t k = i; k < j; ++k) {
      GlobalValue::LinkageTypes Linkage = Globals[k]->getLinkage();
      std::string Name = Globals[k]->getName();

      Constant *Idx[2] = {
        ConstantInt::get(Int32Ty, 0),
        ConstantInt::get(Int32Ty, k-i)
      };
      Constant *GEP = ConstantExpr::getInBoundsGetElementPtr(MergedGV, Idx);
      Globals[k]->replaceAllUsesWith(GEP);
      Globals[k]->eraseFromParent();

      if (Linkage != GlobalValue::InternalLinkage) {
        // Generate a new alias...
        auto *PTy = cast<PointerType>(GEP->getType());
        GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
                            Linkage, Name, GEP, &M);
      }

      NumMerged++;
    }
    i = j;
  }

  return true;
}

bool ProfilingPass::doInitialization(Module &M)
{
	LLVMContext& context = M.getContext();
	Function* mainFunc = M.getFunction("main");
	const string moduleName = M.getModuleIdentifier();
	if (mainFunc!=NULL) {
		//BasicBlock* entryBlock = &mainFunc->front();
		Constant* Init = ConstantArray::get(context,moduleName,true);	// Convert it to an LLVM Type
		GlobalVariable* nameStr = new GlobalVariable(Init->getType(), true, GlobalValue::InternalLinkage, Init, "NameStr" );
		M.getGlobalList().push_back( nameStr );						// Insert it into the list of globals for module
		std::vector<Constant*>IndicesC(2);
		IndicesC[0] = Constant::getNullValue(Type::getInt32Ty(context));
		IndicesC[1] = ConstantInt::get(Type::getInt32Ty(context),0);
		Constant *getElemExpr =  ConstantExpr::getGetElementPtr(nameStr, &IndicesC[0], IndicesC.size());
		vector<Value*> initInjectArgs;
		initInjectArgs.push_back( getElemExpr ); 
		FunctionType* initInjectionFuncType = FunctionType::get(Type::getVoidTy(context), 
		vector<const Type*>(1,  PointerType::get(Type::getInt8Ty(context),0)),0); 
		
		//BasicBlock *exitBlock = &mainFunc->back();
		Instruction *I;
		for (inst_iterator fi = inst_begin(mainFunc), fe = inst_end(mainFunc); fi!=fe; ++fi){
			I = &*fi;
			if(isa<ReturnInst>(I))
				break;
		}
		BasicBlock *retblock = I->getParent(); //*retpred = retblock->getSinglePredecessor();
		
		Instruction *term = retblock->getTerminator();
		Constant *endFunc = M.getOrInsertFunction("endProfiling", initInjectionFuncType);
		vector<Value*> countArgs(1);
		//const IntegerType* itype = IntegerType::get(context,32);
		//Value* branchVal = ConstantInt::get(itype, BRANCH );
		CallInst::Create(endFunc, initInjectArgs.begin(), initInjectArgs.end(), "", term);
	}
	else
	{
		Constant* Init = ConstantArray::get(context,moduleName,true);	// Convert it to an LLVM Type
		GlobalVariable* nameStr = new GlobalVariable(Init->getType(), true, GlobalValue::InternalLinkage, Init, "NameStr" );
		M.getGlobalList().push_back( nameStr );
	}

	//***********************************************************************************************************
	//code for loading configure file should be here
	ifstream config ("llfi_configure.txt");
	if (config.is_open())
	{
		// we need to extract information from config file here Qining
		// this loop is used to know if the file is end
		while ( config.good() )
    	{
    		string line;
      		getline (config,line);
      		if(line.empty())	continue;
      		//if the line is empty, just skip.
      		//Any block of configure is started with one specific function
      		unsigned found = line.find("FUNCTION_NAME:");
      		if (found < line.length())
      		{
    			//std::cout << "\nfound FUNCTION_NAME at " << found << '\n';
    			std::string func_name = line.substr (found + string("FUNCTION_NAME:").length(),line.length() - found - string("FUNCTION_NAME:").length());
    			//first, I need to trim it
    			while(func_name[0] == ' ')
    			{
    				func_name.erase(0, 1);
    			}
    			while(func_name[func_name.length() - 1] == ' ')
    			{
    				func_name.erase(func_name.length() - 1, 0);
    			}
    			//so now I've got the name of the function
    			if(func_name.empty())	continue;
				std::cout << "The func_name is " << func_name << "\n";
				map_func_argu[func_name] = set<unsigned int>(); // create entry
				//map_func_fault_type[func_name] = set<unsigned int>(); 
				//second, I need to load argument set and type set
				do
				{
					line.clear();
					getline(config,line); // get the next line
					if(!config.good())	break; // if the new line is the end of file, our job is done.
					if(line.find("ARGUMENT:") < line.length())
					{
						//insert argument id to argument set
						std::string arg_set = line.substr(line.find("ARGUMENT:")+string("ARGUMENT:").length(), line.length() - line.find("ARGUMENT:")-string("ARGUMENT:").length());
						std::string arg;
						while(!arg_set.empty())
						{
							while(arg_set[0] <= '9' && arg_set[0] >= '0')
							{
								arg.append(arg_set.substr(0,1));
								if(!arg_set.empty())	arg_set.erase(0,1);
							}
							if(!arg.empty())
							{
								unsigned int arg_num = atoi(arg.c_str()) - 1;
								map_func_argu[func_name].insert(arg_num);
								std::cout << "\tinclude arg: " << arg_num+1 << "\n";
							}
							arg.clear();
//.........这里部分代码省略.........

/// Evaluate all instructions in block BB, returning true if successful, false
/// if we can't evaluate it.  NewBB returns the next BB that control flows into,
/// or null upon return.
bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
                              BasicBlock *&NextBB) {
  // This is the main evaluation loop.
  while (1) {
    Constant *InstResult = nullptr;

    DEBUG(dbgs() << "Evaluating Instruction: " << *CurInst << "\n");

    if (StoreInst *SI = dyn_cast<StoreInst>(CurInst)) {
      if (!SI->isSimple()) {
        DEBUG(dbgs() << "Store is not simple! Can not evaluate.\n");
        return false;  // no volatile/atomic accesses.
      }
      Constant *Ptr = getVal(SI->getOperand(1));
      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) {
        DEBUG(dbgs() << "Folding constant ptr expression: " << *Ptr);
        Ptr = ConstantFoldConstantExpression(CE, DL, TLI);
        DEBUG(dbgs() << "; To: " << *Ptr << "\n");
      }
      if (!isSimpleEnoughPointerToCommit(Ptr)) {
        // If this is too complex for us to commit, reject it.
        DEBUG(dbgs() << "Pointer is too complex for us to evaluate store.");
        return false;
      }

      Constant *Val = getVal(SI->getOperand(0));

      // If this might be too difficult for the backend to handle (e.g. the addr
      // of one global variable divided by another) then we can't commit it.
      if (!isSimpleEnoughValueToCommit(Val, SimpleConstants, DL)) {
        DEBUG(dbgs() << "Store value is too complex to evaluate store. " << *Val
              << "\n");
        return false;
      }

      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) {
        if (CE->getOpcode() == Instruction::BitCast) {
          DEBUG(dbgs() << "Attempting to resolve bitcast on constant ptr.\n");
          // If we're evaluating a store through a bitcast, then we need
          // to pull the bitcast off the pointer type and push it onto the
          // stored value.
          Ptr = CE->getOperand(0);

          Type *NewTy = cast<PointerType>(Ptr->getType())->getElementType();

          // In order to push the bitcast onto the stored value, a bitcast
          // from NewTy to Val's type must be legal.  If it's not, we can try
          // introspecting NewTy to find a legal conversion.
          while (!Val->getType()->canLosslesslyBitCastTo(NewTy)) {
            // If NewTy is a struct, we can convert the pointer to the struct
            // into a pointer to its first member.
            // FIXME: This could be extended to support arrays as well.
            if (StructType *STy = dyn_cast<StructType>(NewTy)) {
              NewTy = STy->getTypeAtIndex(0U);

              IntegerType *IdxTy = IntegerType::get(NewTy->getContext(), 32);
              Constant *IdxZero = ConstantInt::get(IdxTy, 0, false);
              Constant * const IdxList[] = {IdxZero, IdxZero};

              Ptr = ConstantExpr::getGetElementPtr(nullptr, Ptr, IdxList);
              if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
                Ptr = ConstantFoldConstantExpression(CE, DL, TLI);

            // If we can't improve the situation by introspecting NewTy,
            // we have to give up.
            } else {
              DEBUG(dbgs() << "Failed to bitcast constant ptr, can not "
                    "evaluate.\n");
              return false;
            }
          }

          // If we found compatible types, go ahead and push the bitcast
          // onto the stored value.
          Val = ConstantExpr::getBitCast(Val, NewTy);

          DEBUG(dbgs() << "Evaluated bitcast: " << *Val << "\n");
        }
      }

      MutatedMemory[Ptr] = Val;
    } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CurInst)) {
      InstResult = ConstantExpr::get(BO->getOpcode(),
                                     getVal(BO->getOperand(0)),
                                     getVal(BO->getOperand(1)));
      DEBUG(dbgs() << "Found a BinaryOperator! Simplifying: " << *InstResult
            << "\n");
    } else if (CmpInst *CI = dyn_cast<CmpInst>(CurInst)) {
      InstResult = ConstantExpr::getCompare(CI->getPredicate(),
                                            getVal(CI->getOperand(0)),
                                            getVal(CI->getOperand(1)));
      DEBUG(dbgs() << "Found a CmpInst! Simplifying: " << *InstResult
            << "\n");
    } else if (CastInst *CI = dyn_cast<CastInst>(CurInst)) {
      InstResult = ConstantExpr::getCast(CI->getOpcode(),
                                         getVal(CI->getOperand(0)),
                                         CI->getType());
//.........这里部分代码省略.........

void InitializeSoftBound:: constructCheckHandlers(Module & module){

  Type* void_ty = Type::getVoidTy(module.getContext());

  Type* void_ptr_ty = PointerType::getUnqual(Type::getInt8Ty(module.getContext()));
  Type* size_ty = Type::getInt64Ty(module.getContext());

  module.getOrInsertFunction("__softboundcets_spatial_load_dereference_check",
                             void_ty, void_ptr_ty, void_ptr_ty, 
                             void_ptr_ty, size_ty, NULL);

  module.getOrInsertFunction("__softboundcets_spatial_store_dereference_check", 
                             void_ty, void_ptr_ty, void_ptr_ty, 
                             void_ptr_ty, size_ty, NULL);

  module.getOrInsertFunction("__softboundcets_temporal_load_dereference_check", 
                             void_ty, void_ptr_ty, size_ty, 
                             void_ptr_ty, void_ptr_ty, NULL);

  module.getOrInsertFunction("__softboundcets_temporal_store_dereference_check", 
                             void_ty, void_ptr_ty, size_ty, 
                             void_ptr_ty, void_ptr_ty, NULL);


  Function* global_init = (Function *) module.getOrInsertFunction("__softboundcets_global_init", 
                                                                  void_ty, NULL);

  global_init->setDoesNotThrow();
  global_init->setLinkage(GlobalValue::InternalLinkage);

  BasicBlock* BB = BasicBlock::Create(module.getContext(), 
                                      "entry", global_init);
  
  Function* softboundcets_init = (Function*) module.getOrInsertFunction("__softboundcets_init", void_ty, Type::getInt32Ty(module.getContext()), NULL);

  
  SmallVector<Value*, 8> args;
  Constant * const_one = ConstantInt::get(Type::getInt32Ty(module.getContext()), 1);
  
  args.push_back(const_one);
  Instruction* ret = ReturnInst::Create(module.getContext(), BB);
  
  CallInst::Create(softboundcets_init, args, "", ret);



  Type * Int32Type = IntegerType::getInt32Ty(module.getContext());
  std::vector<Constant *> CtorInits;
  CtorInits.push_back(ConstantInt::get(Int32Type, 0));
  CtorInits.push_back(global_init);
  StructType * ST = ConstantStruct::getTypeForElements(CtorInits, false);
  Constant * RuntimeCtorInit = ConstantStruct::get(ST, CtorInits);

  //
  // Get the current set of static global constructors and add the new ctor
  // to the list.
  //
  std::vector<Constant *> CurrentCtors;
  GlobalVariable * GVCtor = module.getNamedGlobal ("llvm.global_ctors");
  if (GVCtor) {
    if (Constant * C = GVCtor->getInitializer()) {
      for (unsigned index = 0; index < C->getNumOperands(); ++index) {
        CurrentCtors.push_back (dyn_cast<Constant>(C->getOperand (index)));
      }
    }
  }
  CurrentCtors.push_back(RuntimeCtorInit);

  //
  // Create a new initializer.
  //
  ArrayType * AT = ArrayType::get (RuntimeCtorInit-> getType(),
                                   CurrentCtors.size());
  Constant * NewInit = ConstantArray::get (AT, CurrentCtors);

  //
  // Create the new llvm.global_ctors global variable and remove the old one
  // if it existed.
  //
  Value * newGVCtor = new GlobalVariable (module,
                                          NewInit->getType(),
                                          false,
                                          GlobalValue::AppendingLinkage,
                                          NewInit,
                                          "llvm.global_ctors");
  if (GVCtor) {
    newGVCtor->takeName (GVCtor);
    GVCtor->eraseFromParent ();
  }



}

	virtual bool runOnModule(Module &M) {

		LLVMContext &C = M.getContext();
		Function *printError_func = (Function*)M.getOrInsertFunction("printErrorMessage", Type::getVoidTy(C), NULL);

		BasicBlock* entryBlock = BasicBlock::Create(C, "", printError_func);
		IRBuilder<> builder(entryBlock);

		Constant *msg = ConstantArray::get(C, "ERROR!  Array Index Out of Bounds", true);

		Constant *zero_32 = Constant::getNullValue(IntegerType::getInt32Ty(C));
		Constant *gep_params[] = {zero_32, zero_32};


		GlobalVariable *errorMsg = new GlobalVariable(M, msg->getType(), true, GlobalValue::InternalLinkage, msg, "errorMsg");
		Function *puts_func = (Function*)(M.getOrInsertFunction("puts", IntegerType::getInt32Ty(C), PointerType::getUnqual(IntegerType::getInt8Ty(C)), NULL));
		Constant *msgptr = ConstantExpr::getGetElementPtr(errorMsg, gep_params);

		Value *puts_params[] = {msgptr};

		CallInst *puts_call = builder.CreateCall(puts_func, puts_params);
		puts_call->setTailCall(false);

		Function *exit_func = cast<Function>(M.getOrInsertFunction("exit", IntegerType::getVoidTy(C), Type::getInt32Ty(C),NULL));

		Value *exit_val = ConstantInt::get(IntegerType::getInt32Ty(C), 1);
		
		//create exit block.  This block prints the error and calls exit system function
		BasicBlock* exitBlock = BasicBlock::Create(C, "exitBlock", printError_func);
		builder.CreateBr(exitBlock);
		builder.SetInsertPoint(exitBlock);


		builder.CreateCall(exit_func,exit_val);
		builder.CreateBr(exitBlock);

		int checksInserted = 0;

		for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI)
		{
			//leave func defs alone
			if (!MI->isDeclaration()) 
			{
				for (inst_iterator I = inst_begin(*MI), E = inst_end(*MI); I != E; ++I)
				{
					Instruction *inst = &*I;
					
					if(GetElementPtrInst *gep = dyn_cast<GetElementPtrInst>(inst))
					{
						if (const ArrayType *ar = dyn_cast<ArrayType>(gep->getPointerOperandType()->getElementType()))
						{           
							//increment checks inserted counter
							checksInserted++;
	
							//create split in basic block for function call insertion (branch)
							Instruction* next = inst->getNextNode();
							BasicBlock* oldBlock = inst->getParent();
							BasicBlock* newBlock = SplitBlock(oldBlock, next, this);

							//get upper limit and index used
							unsigned upperLim = ar->getNumElements();
							int index = gep->getNumOperands() - 1;
							Value *vIndexUsed = gep->getOperand(index);
							Value *vUpperLimit = ConstantInt::get(vIndexUsed->getType(), upperLim);

							BasicBlock* checkUpperBlock = BasicBlock::Create(C, "checkUpperBlock", MI, newBlock);
							BasicBlock* checkLowerBlock = BasicBlock::Create(C, "checkLowerBlock", MI, checkUpperBlock);
							
							builder.SetInsertPoint(oldBlock);
							
							//remove old terminator
							TerminatorInst* term = oldBlock->getTerminator();
							term->eraseFromParent();
							//insert new one
							builder.CreateBr(checkUpperBlock);
							
							//configure uppper bound test
							builder.SetInsertPoint(checkUpperBlock);
							Value* condUpperInst = builder.CreateICmpSLT(vIndexUsed, vUpperLimit, "checkUpperBounds");
							BasicBlock* errorBlock = BasicBlock::Create(C, "errorBlock", MI, newBlock);
							builder.CreateCondBr(condUpperInst, checkLowerBlock, errorBlock);

							//configure lower bound test
							builder.SetInsertPoint(checkLowerBlock);
							Value *vLowerLimit = ConstantInt::get(vIndexUsed->getType(), -1);
							Value *condLowerInst = builder.CreateICmpSGT(vIndexUsed, vLowerLimit, "checkLowerBounds");
							builder.CreateCondBr(condLowerInst, newBlock, errorBlock);

							//setup error block.  All this block does is call func to print error and exit
							builder.SetInsertPoint(errorBlock);
							builder.CreateCall(printError_func);
							builder.CreateBr(errorBlock);
						}
					}				
				}
			}
		}
		errs() << "This pass has inserted " << checksInserted << " checks\n";
      return true;
	}

// ResolveConstantExpr - Resolve the constant expression until it stop
// yielding other constant expressions.
CstExprResTy ELFWriter::ResolveConstantExpr(const Constant *CV) {
  const TargetData *TD = TM.getTargetData();
  
  // There ins't constant expression inside others anymore
  if (!isa<ConstantExpr>(CV))
    return std::make_pair(CV, 0);

  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
  switch (CE->getOpcode()) {
  case Instruction::BitCast:
    return ResolveConstantExpr(CE->getOperand(0));
  
  case Instruction::GetElementPtr: {
    const Constant *ptrVal = CE->getOperand(0);
    SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
    int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0],
                                          idxVec.size());
    return std::make_pair(ptrVal, Offset);
  }
  case Instruction::IntToPtr: {
    Constant *Op = CE->getOperand(0);
    Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(CV->getContext()),
                                      false/*ZExt*/);
    return ResolveConstantExpr(Op);
  }
  case Instruction::PtrToInt: {
    Constant *Op = CE->getOperand(0);
    const Type *Ty = CE->getType();

    // We can emit the pointer value into this slot if the slot is an
    // integer slot greater or equal to the size of the pointer.
    if (TD->getTypeAllocSize(Ty) == TD->getTypeAllocSize(Op->getType()))
      return ResolveConstantExpr(Op);

    llvm_unreachable("Integer size less then pointer size");
  }
  case Instruction::Add:
  case Instruction::Sub: {
    // Only handle cases where there's a constant expression with GlobalValue
    // as first operand and ConstantInt as second, which are the cases we can
    // solve direclty using a relocation entry. GlobalValue=Op0, CstInt=Op1
    // 1)  Instruction::Add  => (global) + CstInt
    // 2)  Instruction::Sub  => (global) + -CstInt
    const Constant *Op0 = CE->getOperand(0); 
    const Constant *Op1 = CE->getOperand(1); 
    assert(isa<ConstantInt>(Op1) && "Op1 must be a ConstantInt");

    CstExprResTy Res = ResolveConstantExpr(Op0);
    assert(isa<GlobalValue>(Res.first) && "Op0 must be a GlobalValue");

    const APInt &RHS = cast<ConstantInt>(Op1)->getValue();
    switch (CE->getOpcode()) {
    case Instruction::Add: 
      return std::make_pair(Res.first, RHS.getSExtValue());
    case Instruction::Sub:
      return std::make_pair(Res.first, (-RHS).getSExtValue());
    }
  }
  }

  report_fatal_error(CE->getOpcodeName() +
                     StringRef(": Unsupported ConstantExpr type"));

  return std::make_pair(CV, 0); // silence warning
}

/// CleanupAndPrepareModules - Get the specified modules ready for code
/// generator testing.
///
static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
                                     Module *Safe) {
  // Clean up the modules, removing extra cruft that we don't need anymore...
  Test = BD.performFinalCleanups(Test);

  // If we are executing the JIT, we have several nasty issues to take care of.
  if (!BD.isExecutingJIT()) return;

  // First, if the main function is in the Safe module, we must add a stub to
  // the Test module to call into it.  Thus, we create a new function `main'
  // which just calls the old one.
  if (Function *oldMain = Safe->getFunction("main"))
    if (!oldMain->isDeclaration()) {
      // Rename it
      oldMain->setName("llvm_bugpoint_old_main");
      // Create a NEW `main' function with same type in the test module.
      Function *newMain = Function::Create(oldMain->getFunctionType(),
                                           GlobalValue::ExternalLinkage,
                                           "main", Test);
      // Create an `oldmain' prototype in the test module, which will
      // corresponds to the real main function in the same module.
      Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
                                                GlobalValue::ExternalLinkage,
                                                oldMain->getName(), Test);
      // Set up and remember the argument list for the main function.
      std::vector<Value*> args;
      for (Function::arg_iterator
             I = newMain->arg_begin(), E = newMain->arg_end(),
             OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
        I->setName(OI->getName());    // Copy argument names from oldMain
        args.push_back(I);
      }

      // Call the old main function and return its result
      BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
      CallInst *call = CallInst::Create(oldMainProto, args, "", BB);

      // If the type of old function wasn't void, return value of call
      ReturnInst::Create(Safe->getContext(), call, BB);
    }

  // The second nasty issue we must deal with in the JIT is that the Safe
  // module cannot directly reference any functions defined in the test
  // module.  Instead, we use a JIT API call to dynamically resolve the
  // symbol.

  // Add the resolver to the Safe module.
  // Prototype: void *getPointerToNamedFunction(const char* Name)
  Constant *resolverFunc =
    Safe->getOrInsertFunction("getPointerToNamedFunction",
                    Type::getInt8PtrTy(Safe->getContext()),
                    Type::getInt8PtrTy(Safe->getContext()),
                       (Type *)0);

  // Use the function we just added to get addresses of functions we need.
  for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
    if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
        !F->isIntrinsic() /* ignore intrinsics */) {
      Function *TestFn = Test->getFunction(F->getName());

      // Don't forward functions which are external in the test module too.
      if (TestFn && !TestFn->isDeclaration()) {
        // 1. Add a string constant with its name to the global file
        Constant *InitArray =
          ConstantDataArray::getString(F->getContext(), F->getName());
        GlobalVariable *funcName =
          new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
                             GlobalValue::InternalLinkage, InitArray,
                             F->getName() + "_name");

        // 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
        // sbyte* so it matches the signature of the resolver function.

        // GetElementPtr *funcName, ulong 0, ulong 0
        std::vector<Constant*> GEPargs(2,
                     Constant::getNullValue(Type::getInt32Ty(F->getContext())));
        Value *GEP = ConstantExpr::getGetElementPtr(funcName, GEPargs);
        std::vector<Value*> ResolverArgs;
        ResolverArgs.push_back(GEP);

        // Rewrite uses of F in global initializers, etc. to uses of a wrapper
        // function that dynamically resolves the calls to F via our JIT API
        if (!F->use_empty()) {
          // Create a new global to hold the cached function pointer.
          Constant *NullPtr = ConstantPointerNull::get(F->getType());
          GlobalVariable *Cache =
            new GlobalVariable(*F->getParent(), F->getType(),
                               false, GlobalValue::InternalLinkage,
                               NullPtr,F->getName()+".fpcache");

          // Construct a new stub function that will re-route calls to F
          FunctionType *FuncTy = F->getFunctionType();
          Function *FuncWrapper = Function::Create(FuncTy,
                                                   GlobalValue::InternalLinkage,
                                                   F->getName() + "_wrapper",
                                                   F->getParent());
          BasicBlock *EntryBB  = BasicBlock::Create(F->getContext(),
//.........这里部分代码省略.........